In Sutton & Barto's book (2nd ed) page 149, there is the equation 7.11
I am having a hard time understanding this equation.
I would have thought that we should be moving $Q$ towards $G$, where $G$ would be corrected by importance sampling, but only $G$, not $G-Q$, therefore I would have thought that the correct equation would be of the form
$Q \leftarrow Q + \alpha (\rho G - Q)$
$Q \leftarrow Q + \alpha \rho (G - Q)$
I don't get why the entire update is weighted by $\rho$ and not only the sampled return $G$.